An insulation assembly is commonly used in the electric power industry for electric insulation. The insulation assembly generally comprises an insulation pipe, an insulation umbrella group formed on the insulation pipe, and a metal flange connected to an end of the insulation pipe.
The cost of the metal flange is very high, however, which increases the cost of the entire insulation assembly. Further, a gap often forms between the metal flange and the insulation pipe because the metal flange and the insulation pipe are made of different materials with different thermal expansion coefficients. As a result, an insulation gas, for example sulfur hexaflouride (SF6), filled in the insulation pipe leaks out through the gap between the metal flange and the insulation pipe. The metal flange also is very heavy in weight and reduces the electrical performance of the insulation assembly.